Stable lithium plating/stripping electrochemistry promoted by a MnO2 modified copper current collector for stable lithium metal anodes

Abstract

Due to lower redox potential and excellent theoretical capacity, lithium metal anodes are being explored for high-energy density next generation rechargeable batteries. The lithium metal anode is dragged out of use in practical applications because of its high reactivity and considerable volume expansion, which also cause an unstable solid electrolyte interface, severe side reactions, dendrite growth, electrode degradation, low coulombic efficiency, and even significant safety concerns. To establish a stable solid electrolyte interphase (SEI) and avoid dendrite issues, a variety of methods are being investigated. It is also shown that the initial Li nucleation, which determines the interface and reversibility of future cycles, may be aided by the deposition of a thin film of MnO₂ on the current collector. By lowering the electrode's nucleation barrier, the lithiophilic properties of MnO₂ may successfully promote smooth and homogeneous plating of Li on the Cu collector surface. Such a MnO₂ nanorod structure enables effective electron conduction between the conductive substrate and lithiophilic layer, improves Li-ion transfer kinetics, and significantly minimizes the local current inhomogeneity. The structure effectively prevents dendritic growth and volume change as evidenced by its ability to retain a constant coulombic efficiency over an extended period of time of up to 186 h (2 mA cm⁻²). This technology has made it possible to demonstrate Li metal anodes with excellent coulombic efficiency, paving the way for steady, efficient, and long-cycle life Li metal batteries with less Li loading.